in a village tree and above a community watering hole, respect ively. The rock hyrax, Heterohyrax brucei hoogstraali, occupied a ledge a few dozen yards above a group of hillside huts.

A significant observation of all stages of the kennel tick feeding on European rabbits, Oryctolagus cuniculus, in a forest near Casablanca has been reported by Blanc and Bruneau (1954). In the Yemen, tremendous infestations, representing varying proportions of all stages, were found on all hares examined (Sanborn and Hoogstraal 1953; Hoogstraal, ms.). In Egypt the same is true of hares, some two hundred of which have been examined. Equatoria Province records show numerous adults on hares and grass rabbits (or grass hares, Poelagus), and in Bahr El Ghazal Province all stages were taken from the several specimens of hares. Indeed, it appears that in both the Ethiopian and Palearctic Faunal Re gions of Africa and Arabia, lagomorphs may be exceedingly im portant as secondary hosts or possibly even as primary hosts of all stages of the kennel tick. Yet, there is no evidence avail able to indicate that domestic rabbits kept in hutches are seriously infested by this parasite, although as a rule merely housing any animal seems to be an important factor leading to its being attacked by this parasite. European rabbits, an in tegral part of every Bedouin tenthold in Egypt, are usually infested. These rabbits, which seldom venture far from their owners' tents, are carried from place to place in a bag on the side of a camel when Bedouins move in search of pasturage. Out side of Africa, hares have been found infested by notable numbers of this tick in Anatolia (Hoogstraal, ms.).

Without going into detail, a survey of field data indicates that hedgehogs may play a role in supporting this tick second only to that of lagomorphs. These spiny insectivores are com monly though seldom heavily infested.

In Egypt, most kinds of desert rodents are occasionally infested by larvae and nymphs, as are also grass rats, Arvicanthis n. niloticus, in cultivated areas. These data are too voluminous and complex to evaluate in the present study. It is, however, apparent that in field situations the life history differs from that of urban populations.

Avian Hosts

It should be of some interest to present the available African records of avian parasitism by R. s. sanguineus in the hope of in stigating further investigation of this subject. The immediate concern over this problem is the fact that specimens from birds in Equatoria Province have much lighter interstitial punctations than those from mammals in the same Province. Material from birds resembles the majority of specimens from northern Sudan and Egypt and is in closer conformity to the general conception of the appearance of this species.

Recorded African avian hosts are the following:

Ostrich

Struthio camelus massaicus in Kenya (Neumann 1911,1912). S. camelus subsp. in Uganda (Theiler, unpublished). S. camelus australis in Mozambique (Santos Dias 1952D).

Bustards

Lissotis melanogaster in Mozambique Specimens in BM (NH) and from Sudan (Kordofan Province record above). "Greater bustard" in Kenya (Lewis 1934). "Lesser" and "greater" bustards in Sudan (various Province records above). Neotis cafra denhami in Sudan (Equatoria Province records above). Neotis cafra jacksoni in Uganda (Theiler, unpublished).7

Secretary bird

Sagittarius serpentarius in Sudan (Khartoum zoo record above) and in Kenya (Lewis 1934).

Hornbill

Bycanistes albotibialis from Yaounde, French Cameroons (J. Mouchet legit, HH det.).

Storks

Sphenorhynchus abdimii in the Sudan (Equatoria Province record above). Leptoptilos crumeniferus in Uganda (Theiler, unpublished).

Ibis

Hagedashia hagedash subsp. (Neumann 1911) and as "Theristicus leucocephalus in Tanganyika (Neumann 1907°C,1910B).

Hawks, Kites, Buzzards, Eagles, and Owls

Kite in the Sudan (King 1926 and Khartoum record above). "Large vulture" in the Sudan (Blue Nile Province record above). Butastur rufipennis in Belgian Congo (Bequaert 1931). Eagle owl, Bubo bubo ascalaphus (= Strix ascalaphus) in Egypt (Neumann 1901, 1911).

Pigeon

"Ringed pigeon" in South Africa (Howard 1908).

There appear to be no African records of this tick from domestic fowls.

Specimens parasitizing birds are usually found on the crown of the head, near the eyes, around or in the ears, at the base of the skull, or in folds of skin beside the beak.

BIOLOGY

Laboratory studies on the general biology of the kennel tick are rather complete. However, field biology and ecology have been much neglected. The biology of this form when confined to houses harboring dogs, although accepted as being well known, has not been adequately studied.

Numerous biological and ecological questions concerning the kennel tick remain to be answered. Why is the density and distribution of African populations so uneven? What is the

significance of morphological variations such as the lightly punc
tate forms from Equatoria Province birds in an area where most of
those parasitizing mammals are heavily punctate? What "biological
strains" or varieties exist in Africa and do some or all of these
react with equal facility to domestication? What is the life
cycle under field conditions and what are the host predilections
of the immature and adult stages away from human and domestic
canine habitations? Why does parasitism of persons and bou
tonneuse fever appear to be so much more common in north
western Africa than elsewhere on this continent (and why is
boutonneuse fever absent in Egypt)? Just what is there about
a habitation shared by man and dogs, whether it be an African
hut or a Florida mansion, that is so much more attractive to
this tick than a fox den in a rocky hillside? Is the greater
incidence of parasitism of all domestic non-canine animals in
the Near East, as compared with tropical Africa, merely a matter
of host availability? These are but a few of the innumerable
inquiries that suggest themselves as a result of our lack of
specific information concerning this common tick.

Life Cycle

The life cycle of R. s. sanguineus has been studied, under laboratory conditions, by Christophers (1907), Hooker, Bishopp, and Wood (1912)*, Patton and Cragg (1913) with techniques il lustrated, Nuttall (1915), and Regendanz and Reichenow (1931). In the discussion below, less specialized life cycle reports or studies for special purposes are noted following the sum mary of the above-mentioned papers.

All observers agree that this is a three-host tick. Varia tion in reports of length of feeding time of each stage may be due to the kind of host used in laboratory experiments (see below). During nonfeeding phases temperature and humidity exert considerable influence on the length of the life cycle. Nuttall concluded that feeding times are constant, irrespective of temperature variations, and that only the nonfeeding phases are affected by these variables (see also discussion of this aspect under H. dromedarii, p. 428).

*The extensive data in this important paper are not reviewed here.

!

In Nuttall's laboratory experiments, larvae fed on dogs and rabbits, nymphs on dogs, jackals, and hedgehogs, and adults on dogs and jackals. Larvae commenced feeding three to seven days after emergence, nymphs began about the same length of time after molting, and adults about a week after molting. Larvae fed for three to eight days (mostly four days) (temperature ranged from 6.5°C. to 20°C.). Nymphs fed for three to eleven days (mostly four days), on the dog or jackal; but when hedgehogs were used, the feeding time (ten to seventeen days) was about doubled* (temperature ranged from 8°C. to 18°C.). Females fed from one to three weeks (mostly eight days) but males remained attached indefinitely and transferred to another host if the first animal

died.

As already stated, the length of intervals during which ticks are off the host appears to be influenced by temperature (though more exact and extensive research is certainly required). In Nuttall's tests, eggs hatched in from seventeen to nineteen days at 30°C. but required 75 days at 12°C. Larvae molted to nymphs from five to eight days after completing feeding (at 30°C.), and nymphs molted to adults in eleven or twelve days after feeding (at 30°C.). Oviposition commenced three to six days (average three or four days) after females left the host, when maintained at 30°C.; but at 12°C. they commenced oviposition after 25 days. Egglaying lasted for from nine to fifteen days.

The life cycle, under favorable conditions, may be completed in as little as 63 days. Under unfavorable conditions, it may be prolonged for many months.

By way of contrast to Nuttall's findings and because the records of Christophers (1907) "are not complete and do not indicate the temperature at which the specimens were reared" Sapre (1945) undertook similar experiments in India at 7500 feet altitude, with dogs said to be the hosts for all stages. Nonfeeding ticks were observed at 22°C. (eight degrees lower

*A similar situation has been reported for Ornithodoros arenicolous whose females feed on mice for 45 minutes but on hedgehogs for 70 minutes (average), and whose males feed on mice for 45 minutes and on hedgehogs for 57 minutes (average) (Hoogstraal 1953C).